1. Field of the Invention
The invention refers to an accessory device for use on a sewing machine having a thread cutter that performs its cutting in a stop position thereof.
2. Description of the Prior Art
Sewing machines comprising thread cutters are known in the art, such machines being built to make use of positioning motors. The thread cutter is activated in response to a cutting pulse from an associated positioning motor, provided that its position corresponds to a predetermined stop position. The thread cutter does its cutting at a moment in which the thread feeder of the sewing machine has reached its uppermost position. This corresponds to the moment the machine is made to stop to enable the operator to displace or remove the sewn article from under the sewing foot. The kinematics of the motions of the conventional thread feeder and the needle bar is such, that the uppermost position of the thread feeder fails to coincide with the uppermost position of the needle bar. At the moment the thread feeder has reached its uppermost position, the needle bar is well on its downward motion, so that a distance of only 13 to 15 mm remains between the stitch plate and the tip of the needle, i.e. the sewing foot. However, if the sewn goods are thick or bulky the distance required is larger, and to achieve it, the sewing machine must be manually rotated backward by approximately 90.degree.. This, however, is time consuming, unreliable and cannot very well be expected to be performed by the sewing machine operator.